Dear Discourse,
Whenever my post contains the word substring, an error 403 is displayed:
For the time being, I just used sub-string instead, but that’s not a workable solution.
You can see my post here. Is there any way to avoid this? I have tried to use all possible text formatting but nothing helps. Thank you!
I wasn’t able to replicate this 
Do you have a custom theme/theme component? If you try from another account, the same happens? Do you see any errors in https://ax.docentric.com/forum/logs? Any errors in the browser’s console?
there are alot of warning in your console
The FetchEvent for “https://www.google-analytics.com/analytics.js” resulted in a network error response: the promise was rejected.
analytics.js:1 Failed to load resource: net::ERR_FAILED
NetworkFirst.mjs:167 Uncaught (in promise) no-response: no-response :: [{“url”:“https://www.google-analytics.com/analytics.js”}]
at a.makeRequest (https://ax.docentric.com/forum/javascripts/workbox/workbox-strategies.prod.js:1:2145)
DevTools failed to load source map: Could not load content for https://ax.docentric.com/assets/service-worker-0f46bc4160bec3db67d0b8d229c83dc9211fdb898d847ab96d6e2bafea704cd0.js.map: HTTP error: status code 404, net::ERR_HTTP_RESPONSE_CODE_FAILURE
DevTools failed to load source map: Could not load content for https://ax.docentric.com/assets/browser-detect-115ab5953de1b5bb122bfb26b757f5391dd8d1d2aef2b81baf7b59aee99d9f34.js.map: HTTP error: status code 404, net::ERR_HTTP_RESPONSE_CODE_FAILURE
DevTools failed to load source map: Could not load content for https://ax.docentric.com/assets/application-38e7ba8d44d8f6050114fd240f73ac6e4ed6933ec58a0117bc3ca11067780c4b.js.map: HTTP error: status code 404, net::ERR_HTTP_RESPONSE_CODE_FAILURE
DevTools failed to load source map: Could not load content for https://ax.docentric.com/assets/locales/en-068f6c21bf76a00056a9f45ebfb4907c9be9e928d441f97d7bed92f58ea0341b.js.map: HTTP error: status code 404, net::ERR_HTTP_RESPONSE_CODE_FAILURE
DevTools failed to load source map: Could not load content for https://ax.docentric.com/assets/plugins/discourse-akismet-b158ed3716457724147fc14a3b6cf4c6234b3b715dcbb2dc830a349d3da3a5db.js.map: HTTP error: status code 404, net::ERR_HTTP_RESPONSE_CODE_FAILURE
DevTools failed to load source map: Could not load content for https://ax.docentric.com/assets/vendor-6c7e3fc2df536d0f96baf76e831aad0f2dd61c14b9c86bdd31b870a15ad2a132.js.map: HTTP error: status code 404, net::ERR_HTTP_RESPONSE_CODE_FAILURE
DevTools failed to load source map: Could not load content for https://ax.docentric.com/assets/plugins/discourse-assign-6ae07b894263aacd0ff708b1764c470eda360f57a02669212191d888598658ce.js.map: HTTP error: status code 404, net::ERR_HTTP_RESPONSE_CODE_FAILURE
DevTools failed to load source map: Could not load content for https://ax.docentric.com/assets/plugins/discourse-canned-replies-4477d176c5fc54c994338634c6f9120a849e51cd247e06aa2e07da678ba82407.js.map: HTTP error: status code 404, net::ERR_HTTP_RESPONSE_CODE_FAILURE
DevTools failed to load source map: Could not load content for https://ax.docentric.com/assets/plugins/discourse-data-explorer-89ab050fa4b56fbc2fafe020ff037772f3d3fc57a3591ee0c4cb3daf9238883e.js.map: HTTP error: status code 404, net::ERR_HTTP_RESPONSE_CODE_FAILURE
DevTools failed to load source map: Could not load content for https://ax.docentric.com/assets/plugins/discourse-details-61554ea83ad59329c2d5c9f0390a0498f3e3665deb58d32dc608aeca24fa0bb9.js.map: HTTP error: status code 404, net::ERR_HTTP_RESPONSE_CODE_FAILURE
DevTools failed to load source map: Could not load content for https://ax.docentric.com/assets/plugins/discourse-local-dates-1ce1601fcba226038712e9a1c800257264845949db3581eb2a13004bbd94b58f.js.map: HTTP error: status code 404, net::ERR_HTTP_RESPONSE_CODE_FAILURE
DevTools failed to load source map: Could not load content for https://ax.docentric.com/assets/plugins/discourse-footnote-5d7f9bcc8f1fc30990236f3fe0abfbfc5cc3a490e9d5595f844aeb6d4b86842f.js.map: HTTP error: status code 404, net::ERR_HTTP_RESPONSE_CODE_FAILURE
DevTools failed to load source map: Could not load content for https://ax.docentric.com/assets/plugins/discourse-saved-searches-e84bded10049d1363a0bdd0fb459ca2984821e718323aa0a0d7128a7e9dcf605.js.map: HTTP error: status code 404, net::ERR_HTTP_RESPONSE_CODE_FAILURE
DevTools failed to load source map: Could not load content for https://ax.docentric.com/assets/plugins/discourse-voting-efaecaa7c03601357a43da8e0fed44452daaafb5d213cab42837d1accf20eb68.js.map: HTTP error: status code 404, net::ERR_HTTP_RESPONSE_CODE_FAILURE
DevTools failed to load source map: Could not load content for https://ax.docentric.com/assets/plugins/discourse-presence-e575490133b5e948d5db094ba04f265c777e7d5003f1b418d1b7a38c8f64a317.js.map: HTTP error: status code 404, net::ERR_HTTP_RESPONSE_CODE_FAILURE
DevTools failed to load source map: Could not load content for https://ax.docentric.com/assets/plugins/discourse-solved-be68360ae740ad69b2b4d48fbde314ac17a093b4f5256315469a13677501f9e4.js.map: HTTP error: status code 404, net::ERR_HTTP_RESPONSE_CODE_FAILURE
DevTools failed to load source map: Could not load content for https://ax.docentric.com/assets/plugins/discourse-user-notes-d14c90e2d4da12a15f265abe04860d0b0e9f221ead5ee8cb9373d3972c79887a.js.map: HTTP error: status code 404, net::ERR_HTTP_RESPONSE_CODE_FAILURE
DevTools failed to load source map: Could not load content for https://ax.docentric.com/assets/plugins/discourse-tooltips-3a1d33257615ab498afe95ba168c18d8548069649b07a0b8848eb1b9260ed44e.js.map: HTTP error: status code 404, net::ERR_HTTP_RESPONSE_CODE_FAILURE
DevTools failed to load source map: Could not load content for https://ax.docentric.com/assets/plugins/discourse-narrative-bot-0b1e40d099d739cee23bbad45c2fb5eac1dcaaba028fdc9fa21b9e32930ec40b.js.map: HTTP error: status code 404, net::ERR_HTTP_RESPONSE_CODE_FAILURE
DevTools failed to load source map: Could not load content for https://ax.docentric.com/assets/plugins/docker_manager-4ced9f9c7bda9ba563c04006dbb93828d43f2c7d5b533065717c5a63da77d5fc.js.map: HTTP error: status code 404, net::ERR_HTTP_RESPONSE_CODE_FAILURE
DevTools failed to load source map: Could not load content for https://ax.docentric.com/assets/plugins/lazy-yt-9db193c8caacf2e3b3a24ed4c63699ad497c210f668f467d95380efd00982345.js.map: HTTP error: status code 404, net::ERR_HTTP_RESPONSE_CODE_FAILURE
DevTools failed to load source map: Could not load content for https://ax.docentric.com/assets/plugins/poll-4b9592bd848c2a090591a9b6dda4eba9bf34ad150e4263b26416959ecfde02ad.js.map: HTTP error: status code 404, net::ERR_HTTP_RESPONSE_CODE_FAILURE
DevTools failed to load source map: Could not load content for https://ax.docentric.com/assets/browser-update-eec13eb6f8386f18f10b5dd6ebb7a3598d28421bb796e539b91a7e4a4c5d4c08.js.map: HTTP error: status code 404, net::ERR_HTTP_RESPONSE_CODE_FAILURE
DevTools failed to load source map: Could not load content for https://ax.docentric.com/assets/start-discourse-efa4e5abfbd1b50b5152ffbe64d5dcea9f7c33f766dcc6387e2711f0f2112148.js.map: HTTP error: status code 404, net::ERR_HTTP_RESPONSE_CODE_FAILURE
DevTools failed to load source map: Could not load content for https://ax.docentric.com/assets/google-universal-analytics-v3-706f1d28f0a97f67a47515c96189277240ec4940d968955042066d7873fd1fe8.js.map: HTTP error: status code 404, net::ERR_HTTP_RESPONSE_CODE_FAILURE
Try updating as you running an old version as well
<meta name="generator" content="Discourse 2.8.0.beta2 - https://github.com/discourse/discourse version 15320d432b3045ea4e094a21db6a081f98b8b879">
You might have a WAF enabled that blocks XSS attempts and substring is commonly used in the exploit syntax. If you’re using Cloudflare with WAF enabled that would be the cause.